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Analysis of laminar and turbulent flows with turbomachinery, biotechnology and biomechanical applications
KTH, School of Engineering Sciences (SCI), Mechanics.
2006 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

The goal of this study was initially to gain a better understanding of the effects of rotation on turbulent flow in ducts. Knowledge concerning the influence of rotation on the structures of turbulence is of fundamental importance in many applications, e.g. centrifugal separators, turbines or cooling channels in rotating machinery, as well as meteorology and oceanography. Rapidly rotating duct flow is studied experimentally with rotation numbers in the interval [ 0, 1] . To achieve this, in combination with relatively high Reynolds numbers (5000 – 30000 based on the hydraulic radius), water was used as the working medium. The influence of the rotation on the pressure drop in the duct was investigated and suitable scalings of this quantity were studied. Due to questions that arose in the experimental study, two numerical studies were initiated. The first study probed the effect of rotation and geometrical configuration on the development length for turbulent flow, while the second comprised a direct numerical simulation of turbulent flow in a rotating duct. It is shown that while system rotation does not have a marked effect on the development length in a plane channel, the development length is substantially shortened in a duct.

Additional systems subject to rotation or curvature effects were studied. The laminar flow of fluid in a rotating PCR-cone was analysed analytically and numerically to understand the increased mixing and temperature homogenization. The flow field in the cone was described and the increased mixing was due to a strong boundary layer flow incited by Coriolis and buoyancy effects. Comparisons of the numerical simulations with experiments yielded good results.

A study to quantify the flow of blood in cerebral malformations using three-dimensional videodensitometry was performed. Data from experiments with an idealized flow phantom, as well clinical pathologies, showed that the proposed methodology in conjunction with clinical injection protocols can yield mean flux data with an error less than 20%. Protocol improvements are proposed.

Place, publisher, year, edition, pages
Stockholm: Mekanik , 2006.
Series
Trita-MEK, ISSN 0348-467X ; 2006:06
National Category
Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:kth:diva-3928OAI: oai:DiVA.org:kth-3928DiVA: diva2:10054
Public defence
2006-05-05, Sal F2, Lindstedtsvägen 28, Stockholm, 13:30
Opponent
Supervisors
Available from: 2006-04-27 Created: 2006-04-27 Last updated: 2012-03-21
List of papers
1. Experimental investigation of rapidly rotating turbulent duct flow
Open this publication in new window or tab >>Experimental investigation of rapidly rotating turbulent duct flow
2002 (English)In: Experiments in Fluids, ISSN 0723-4864, E-ISSN 1432-1114, Vol. 33, no 3, 482-487 p.Article in journal (Refereed) Published
Abstract [en]

Rapidly rotating duct flow is studied experimentally with Rotation numbers in the interval [0, 1]. To achieve this, in combination with relatively high Reynolds numbers (5,000-30,000 based on the hydraulic radius), water was used as the working medium. Square and rectangular duct cross-sections were used and the angle between the rotation vector and the main axis of the duct was varied. The influence of the rotation on the pressure drop in the duct was investigated and suitable scalings of this quantity were studied.

Keyword
Channel Flow, Square Duct, Simulations
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-5619 (URN)10.1007/S00348-002-0487-7 (DOI)000178226800014 ()
Note

QC 20100913

Available from: 2006-04-27 Created: 2006-04-27 Last updated: 2014-07-03Bibliographically approved
2. A computational study of developing turbulent flow in a rotationg duct and a rotating channel
Open this publication in new window or tab >>A computational study of developing turbulent flow in a rotationg duct and a rotating channel
2006 (English)Article in journal (Other academic) Submitted
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-5620 (URN)
Note
QS 20120316Available from: 2006-04-27 Created: 2006-04-27 Last updated: 2012-03-16Bibliographically approved
3. Direct numerical simulation of rotating turbulent duct flow
Open this publication in new window or tab >>Direct numerical simulation of rotating turbulent duct flow
2006 (English)In: Journal of turbulence, ISSN 1468-5248Article in journal (Other academic) Submitted
Abstract [en]

A direct simulation of turbulent flow in a rotating square duct using a second-order finite-volume method was performed. The axis of rotation was normal to the direction of the mean flow in theduct. The simulations are performed at Red = 4400 and for Rod = 0 up to 0.77. The strong effect of rotation on both the mean axial and secondary flows is plainly exhibited. A linear increase in the magnitude of the secondary flow was found with increasing rate of rotation. Turbulence quantities are presented to shed some light on the role of the boundary layer structure on the resistance of theflow. The growth of large-scale secondary roll-cells in the axial direction is studied with reference totheir dependence on the rotation number. The case of turbulent flow in a rotating duct that has been tilted 45 degrees around the axis of the mean flow is presented to illustrate the importance of geometric constraints on the characteristics of the flow.

National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-5621 (URN)
Note
QS 20120316Available from: 2006-04-27 Created: 2006-04-27 Last updated: 2012-03-16Bibliographically approved
4. Details of experiments performed on rotating duct flow
Open this publication in new window or tab >>Details of experiments performed on rotating duct flow
2004 (English)Report (Other academic)
Identifiers
urn:nbn:se:kth:diva-5622 (URN)
Note
Internal report, Department ofMechanics, KTH, Stockholm, Sweden. QC 20100913Available from: 2006-04-27 Created: 2006-04-27 Last updated: 2010-09-13Bibliographically approved
5. Rapid PCR amplification of DNA utilizing Coriolis effects
Open this publication in new window or tab >>Rapid PCR amplification of DNA utilizing Coriolis effects
Show others...
2006 (English)In: European Biophysics Journal, ISSN 0175-7571, E-ISSN 1432-1017, Vol. 35, no 6, 453-458 p.Article in journal (Refereed) Published
Abstract [en]

A novel polymerase chain reaction (PCR) method is presented that utilizes Coriolis and centrifugal effects, produced by rotation of the sample disc, in order to increase internal circulatory rates, and with them temperature homogenization and mixing speeds. A proof of concept has been presented by testing a rapid 45-cycle PCR DNA amplification protocol. During the repeated heating and cooling that constitutes a PCR process, the 100 mu L samples were rotated at a speed equivalent to an effective acceleration of gravity of 7,000 g. A cycle time of 20.5 s gave a total process time of 15 min to complete the 45 cycles. A theoretical and numerical analysis of the resulting flow, which describes the increased mixing and temperature homogenization, is presented. The device gives excellent reaction speed efficiency, which is beneficial for rapid PCR.

National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-5623 (URN)10.1007/s00249-006-0052-z (DOI)000238860400001 ()2-s2.0-33745806547 (Scopus ID)
Note
QC 20100913Available from: 2006-04-27 Created: 2006-04-27 Last updated: 2010-09-13Bibliographically approved
6. Flow in a rapidly rotating cone-shaped PCR-tube
Open this publication in new window or tab >>Flow in a rapidly rotating cone-shaped PCR-tube
2011 (English)In: International journal of numerical methods for heat & fluid flow, ISSN 0961-5539, Vol. 21, no 6, 717-735 p.Article in journal (Refereed) Published
Abstract [en]

Purpose - A precise and rapid temperature cycling of a small volume of fluid is vital for an effective DNA replication process using the polymerase chain reaction (PCR). The purpose of this paper is to study the velocity and temperature fields inside a rotating PCR-tube during cooling of the enclosed liquid. Design/methodology/approach - The velocity and temperature fields inside a rotating PCR-tube during cooling of the enclosed liquid are studied. By using computational fluid dynamics, the time development of the flow can be investigated in detail. Owing to the rotation, the flow exhibits features which could never arise in a non-rotating system. Findings - An intricate azimuthal boundary layer flow is presented and explained. The inherent problem of stratification of the temperature is discussed, and different methods towards a remedy are presented. By analyzing the governing equations, some properties of the flow observed in the simulations are explained. It is shown that increasing the rate of rotation does not improve temperature homogenization. Research limitations/implications - The simulations were performed for a limited number of temperature boundary conditions, as well as a specific simulation geometry. Practical implications - The analytical and simulation results offer fundamental insight into the physics behind increased DNA duplication. Further simulations offer possible design improvements. Originality/value - While many studies have probed the effects of buoyancy in rotating cylinders and the development of boundary layers in stratified flows in conical containers rotating around their axis of symmetry, little work has been specifically focused on the case where the axis of rotation is normal to the direction of the stratification, which is the case in the present study.

Keyword
Rotation, Computational fluid mechanics, Coriolis effects, Biomedical flow
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-5624 (URN)10.1108/09615531111148473 (DOI)000296602900003 ()2-s2.0-79960782001 (Scopus ID)
Funder
Swedish e‐Science Research Center
Note
QC 20100913Available from: 2006-04-27 Created: 2006-04-27 Last updated: 2012-05-24Bibliographically approved
7. Cerebral arterial flow characteristics: analysis with 3D video densitometry
Open this publication in new window or tab >>Cerebral arterial flow characteristics: analysis with 3D video densitometry
2006 (English)Article in journal (Other academic) Submitted
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-5625 (URN)
Note
QS 20120316Available from: 2006-04-27 Created: 2006-04-27 Last updated: 2012-03-16Bibliographically approved

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